1. Field of the Invention
The present invention relates to a dynamic pressure bearing and a spindle motor including the same. The present invention also relates to an information recording apparatus including the spindle motor.
2. Description of the Related Art
Recently, there has been an increase in the demand for a reduction in size, an increase in storage capacity, and an increase in rotation rate of hard disk drives (HDDs). In order to meet this demand, bearing mechanisms in HDDs are now typically provided by dynamic pressure bearings rather than traditional ball bearings. In a dynamic pressure bearing, a dynamic pressure generating groove array provided in a so-called herringbone pattern is defined in at least one of a surface of a shaft and a bearing surface. In addition, the shaft and the bearing surface have a minute gap defined therebetween, and a lubricating fluid, such as oil, is arranged within this minute gap.
There has been a demand for a further reduction in size even in HDDs using such dynamic pressure bearings. A reduction in axial dimension is particularly demanded of the dynamic pressure bearings.
Techniques concerning fluid dynamic bearings are disclosed, for example, in JP-A2000-014079, JP-A2005-155689, JP-A2009-133361, and JP-A 2009-136143.